This invention relates to a feedwater heater and, more particularly, to such a heater in which there is an improved distribution of steam at the inlet area of the tube bundle in the desuperheat zone of the heater.
Feedwater heaters are traditionally used to pass steam in thermal contact with feedwater in order to condense the steam and raise the temperature of the feedwater. A typical feedwater heater contains a multiplicity of U-shaped water tubes which extend from a feedwater inlet to a feedwater outlet over which the steam is passed to affect the heat exchange. However, it has been discovered that tube failures often occur in the area where the steam enters the tube bundle, largely due to an uneven distribution of the steam across the tube bundle after it enters the heater. This is largely due to the momentum of the moving steam and the sudden changes in direction of the steam in this area which causes a large portion of the steam flow to concentrate at extreme areas with a greater degree of turbulence. This, in turn, sets up conditions that result in tube vibration and erosion, especially if moist steam conditions exist. As a result, tube fatigue failures occur along with abrasion/impact necking at the baffle supports.